1. Field of the Invention
A locking differential mechanism for racing cars that travel in a given direction around a circular or oval track is disclosed, including locking means for continuously locking the inside wheel shaft to the differential drive train, and normally-engaged overrunning clutch means that are operable during a turn to disengage the outside wheel shaft to a free-running condition when the velocity thereof exceeds that of the inside wheel shaft by a predetermined amount.
2. Brief Description of the Prior Art
As shown by the prior U.S. patents to Knoblock U.S. Pat. Nos. 2,638,794 and 3,397,593, Bokovoy U.S. Pat. No. 3,791,238 and Dissett et al U.S. Pat. No. 4,557,158, it is well known in the patented prior art to provide locking differential mechanisms for vehicles that are operable during a turn in either direction to disengage the overunning outside wheel shaft to a free-wheeling condition when the rotational velocity thereof exceeds the rotational velocity of the inside wheel shaft by a predetermined amount. Center cam means serve to axially displace the overrunning clutch gear away from the central drive member against the force of restoring clutch spring means as long as the overrunning condition exists. When the turn is completed and the velocity of the outside wheel shaft decreases to that of the inside wheel shaft, the clutch gear member is returned by the clutch spring means to its original driven condition in engagement with the central drive member. It is also known to provide holdout ring means for maintaining the outside wheel in the disengaged condition as long as the overrunning condition exists. This type of differential mechanism has utility in all types of on-road and off-road motor driven vehicles.
In the racing car industry, in many types of races, it is common for the racing cars to travel in only one given direction (generally, counterclockwise) along a closed circular or oval track, and consequently the same wheel is always the outside wheel. The present invention was developed to provide an improved locking differential for use with race cars that travel only in a given direction around a closed circular or oval track, which differential affords a rugged durable construction having a low maintenance cost.
Accordingly, a primary object of the present invention is to provide a differential mechanism for race cars that travel in one direction around a closed circular or oval track, including overrunning clutch means that effect disengagement from the drive train of the outer wheel shaft when the rotational velocity thereof exceeds that of the inside wheel shaft by a predetermined amount, and locking means for continuously connecting the inner wheel shaft with the drive train of the differential.
According to a more specific object of the invention, the inside wheel shaft locking means includes an annular locking gear that is non-rotatably splined to the end of the inside wheel shaft, said locking gear including pinion teeth that are in continuous driven engagement with corresponding pinion teeth on one end face of the central driver member that is splined with the differential housing. Pinion teeth on the other end of the center driver member are normally engaged by corresponding pinion teeth on an overrunning clutch member that is connected with the outside wheel shaft. Center cam means are provided for disengaging the clutch member from the center driver member upon the occurrence of an overrunning condition of the outside wheel shaft during a turn. Holdout ring means may be provided for maintaining the clutch member in the disengaged condition as long as the overrunning condition exists.
According to a more specific object of the invention, the pinion teeth on the center drive member, the overrunning clutch member, and the locking gear have a relatively shallow depth, and the remote ends of the side gear of the overrunning clutch means and the locking member are enlarged and extend within counterbores formed in the opposed output shaft openings contained in the end walls of the differential housing. In an embodiment of the invention including holdout ring means, the depth of the pinion teeth each of on the center driver member, the overrunning clutch member, and the locking gear is relatively great. Thrust washer means are provided at the remote ends of the side gear and the locking gear.